Electronic structure and structural stability ofTiCxN1−xalloys

Abstract

We have investigated the structural stability and elastic stiffness of ${\mathrm{TiC}}_{x}$N${}_{1\ensuremath{-}x}$ alloys using the ab initio pseudopotential total-energy method. Our calculation of the formation energy indicates that the alloy is stable in the whole range of the carbon concentration $x$ and the maximum stability is obtained for 0.5$\ensuremath{\lesssim}x$$\ensuremath{\lesssim}$0.75. The bulk modulus increases as nitrogen atoms replace carbon atoms and starts to saturate when the nitrogen concentration exceeds 0.5. Trends in the formation energy and bulk modulus are explained in terms of the detailed electronic structure of titanium carbonitride. Calculated results are in good agreement with available experimental data.